JPS6125547Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a circulation pump for forcedly supplying a heat medium within a heat source for cooling and/or heating operations.

Conventionally, this type of circulation pump has been controlled by a manual switch, or by operating and stopping it in conjunction with a heat exchanger operation switch. However, in the former method, even when the operation of the heat exchanger is stopped due to the operation of a thermostat or the like, the circulation pump continues to be operated, resulting in a waste of electrical energy. Furthermore, in the latter case, a signal line is required between the heat exchanger and the circulation pump, which inconveniently complicates construction and increases installation cost.

The present invention was developed in view of the above points, and it detects the temperature difference between the heat medium flowing out from the heat source and the heat medium flowing in, and generates a signal corresponding to this temperature difference and a separate adjustable discontinuous signal. By activating the circulation pump when it receives at least one of the circulation pump activation signals, it is possible to operate the circulation pump in accordance with the operation of the heat exchanger.

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2. 1 is a commercial power supply, 2 is a hot water circulation pump that forcibly supplies hot water as a heat medium from a heat source to a heat exchange device (not shown) and returns it into the heat source after passing through the heat exchange device; 3 is a hot water circulation pump 2; Relay contacts connected in series, 4 a power transformer, 5 a thermistor for hot water temperature detection arranged on the heat medium outflow side of the heat source, and 6 hot water temperature detection arranged on the heat medium inflow side of the heat source. thermistor for
7 and 8 are resistances for correcting thermistor output characteristics, 9 is a voltage dividing resistor, 10 and 11 are resistances for correcting thermistor output characteristics, 12 and 13 are input resistances, and 14 is a thermistor for detecting hot water temperature, together with the thermistors 5 and 6, for detecting heat from a heat source. A comparator serving as a temperature difference detection means for detecting a temperature difference between the medium inflow side and the medium outflow side and transmitting a circulation pump operation control signal when a temperature difference greater than a predetermined value is detected; 15 is a positive feedback resistor; 16 and 17 are resistors; Piezoresistor, 18 is a comparator that operates as an unstable multivibrator, 19 is a capacitor for timer time constant, 20 is capacitor 1
The charging variable resistor 9 adjusts the charging time constant of the capacitor 19 to make the high level output time of the comparator 18 variable. 21 is a diode, and 22 is a variable resistor for discharging the capacitor 19 connected in series with the diode 21. By adjusting the time constant of discharging the capacitor 19, the low level output time of the comparator 18 is made variable. Note that the charging variable resistor 20, the discharging variable resistor 22, the capacitor 19, and the comparator 18 act as means for discontinuously and periodically transmitting the operation control signal of the circulation pump. The variable resistor 20 and the variable discharge resistor 22 also act as adjusting devices for adjusting the characteristics of the means for transmitting the periodic operation control signal. 23 is a positive feedback resistor, 24 is a relay coil that controls the opening and closing of the relay contact 3 connected to the output terminal of the comparator 18, the output terminal of the comparator 14, the connection point P of the charging variable resistor 20 and the discharging variable resistor 22. Then, the comparator 1
4 and 18 to control the operation of the circulation pump in response to at least one operation control signal from the temperature difference detection means and the means for discontinuously transmitting the operation control signal of the circulation pump. It operates as a control circuit. 25 is a back electromotive voltage canceling diode connected in parallel to the relay coil 24, 26 is a rectifying diode, and 27 is a power source smoothing capacitor.

In the circulation pump control device having such a configuration, when the heat exchange device is in operation, the hot water as a heat medium radiates heat through the heat exchange device, so that the temperature detected by the thermistor 6 for hot water temperature detection is equal to the temperature of the hot water on the inflow side. The resistance is lower than that of the thermistor 5 for temperature detection, and greater than the resistance of the thermistor 5 for hot water temperature detection. At this time, since the non-inverting input of the comparator 14 is lower than the inverting input, the output of the comparator 14 is at a low level. As a result, the relay coil 24 is in an excited state, so the relay contact 3
is in a closed state, and the hot water circulation pump 2 is in an operating state.

On the other hand, when the heat exchange device is stopped, the heat radiation of the hot water via the heat exchange device is drastically reduced, so the temperature of the hot water flowing into the heat source is relatively high, and the difference between the temperature of the hot water flowing out from the heat source becomes less than a predetermined value. At this time, the resistance values of the thermistors 5 and 6 for hot water temperature detection are approximately the same, and due to the presence of the voltage dividing resistor 9, the non-inverting input of the comparator 14 is at a higher level than the inverting input, so the output of the comparator 14 is is at a high level. This results in
The relay coil 24 is demagnetized, the relay contact 3 is opened, and the hot water circulation pump 2 is stopped. Therefore, if the heat exchange device is in a stopped state, the hot water circulation pump 2 is controlled to be in a stopped state.

Even if the heat exchange device is switched from the stopped state to the operating state, the hot water circulation pump 2 will not become active as it is, but the comparator 18 will be connected to the capacitor 19, the charging variable resistor 20, and the discharging variable resistor 22. It operates as an unstable multivibrator that generates pulses with a set period, so
In response to this pulse, the comparator 18 periodically outputs a high level and a low level, and when the comparator 18 outputs a low level, the relay coil 24 is excited, and an exciting current periodically flows through the relay coil 24, causing the relay The hot water circulation pump 2 is activated by the periodic opening and closing of the contact 3.
starts and stops periodically. Specifically, when the timer time constant capacitor 19 starts to be charged via the charging variable resistor 20 and the potential of the capacitor 19 exceeds the potential of the non-inverting input of the comparator 18, the comparator 18 outputs a low level. The relay coil 24 is excited and the capacitor 19 starts discharging via the discharge variable resistor 22. When the potential of the capacitor 19 becomes lower than the potential of the non-inverting input due to this discharge, the comparator 18 outputs a high level, and while the relay coil 24 is demagnetized, charging of the capacitor 19 starts via the charging variable resistor 20. Then, the above operation is repeated in the same manner.

Therefore, when the heat exchange device is in operation due to the periodic operation of the hot water circulation pump 2, a temperature difference is created between the heat medium flowing out from the heat source and the heat medium flowing in.
Thermistor 5, 6 and comparator 14 for hot water temperature detection
The relay coil 24 is maintained in an excited state via the relay contacts 3, and the hot water circulation pump 2 continues to operate via the relay contacts 3.

As described above, in this embodiment, when the heat exchange device is in an operating state, the hot water circulation pump 2 continues to operate, and when the heat exchange device is in a stopped state, the hot water circulation pump 2 operates discontinuously at least occasionally. Therefore, efficient operation of the hot water circulation pump 2 is possible,
Leads to labor savings.

In addition, a charging variable resistor 20 and a discharging variable resistor 2
2 is capable of adjusting its resistance value, so if the hot water piping is relatively short and the round trip time for hot water flowing out from the heat source to flow into the heat source is short, the resistance value of the discharge variable resistor 22 can be made small. Hot water circulation pump 2
By shortening the excitation time of the periodic operation, unnecessary operation of the hot water circulation pump 2 will be reduced, leading to further labor savings. On the other hand, if the hot water piping is long and requires a long round trip time, the discharge variable resistor 22 is set to have a large resistance value accordingly, and the excitation time for the periodic operation of the hot water circulation pump 2 is adjusted accordingly. By increasing the length of time, failure of operation of the hot water circulation pump 2 can be prevented. Furthermore, when the heating load is small or in the case of a heat exchange device that does not repeatedly start and stop due to its characteristics, the charging variable resistor 20 may be set to have a large resistance value to stop the hot water circulation pump 2. The time can be increased, and labor savings can also be achieved from this point of view.

Figure 2 shows the temperature difference C between the temperature of the hot water flowing out from the heat source (boiler) and the temperature of the hot water returning to the heat source due to the activation/stopping state B of the heat exchange device depending on the indoor temperature A, and the hot water according to this temperature difference. It represents the operation/stop D state of the circulation pump 2.

In the above embodiment, the temperature difference is detected by measuring the temperature of the hot water flowing out from the heat source and the temperature of the hot water flowing in. However, if the temperature of the hot water inside the heat source is known, the temperature of the hot water flowing into the heat source can be detected. It is only necessary to provide a thermistor for detecting hot water temperature. In addition, although hot water is used as the heat medium of the heat source and the heat exchange device is used for heat radiation, it is clear that the present invention can also be applied to a case where a low temperature material is used as the heat medium and the heat exchange device is used for heat absorption. Furthermore, it can be applied to any number of heat exchange devices. Further, the means for transmitting the discontinuous circulation pump operation control signal is not limited to the embodiment.

As explained above, according to the present invention, the operation/stop status of the heat exchange device is determined based on the temperature difference between the heat medium flowing out from the heat source and the heat medium flowing in, and the operation of the circulation pump is controlled according to this determination. On the other hand, since an operation control signal with periodicity whose characteristics can be adjusted is sent to the circulation pump, the circulation pump operates continuously when the heat exchanger is in operation, while the circulation pump occasionally operates when the heat exchanger is stopped. Therefore, labor-saving operation of the circulation pump can be achieved. However, since it is only necessary to arrange the signal line in the heat source section, the construction is simple and has the advantage of being inexpensive.

Furthermore, the characteristics of discontinuous operation of the circulation pump are as follows:
Since the time required for the heat medium to go around the heat medium distribution pipe can be set according to the time required for the heat medium to circulate through the heat medium distribution pipe, it is possible to prevent failures in starting the operation of the circulation pump, and also to prevent the operation of the heat exchange device when the heating or cooling return load is small.・There is also the advantage that efficient operation can be performed if stopping operations are not very frequent.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a control device for a circulation pump that is an embodiment of the present invention, and Fig. 2 A, B, C, and D show the indoor temperature, heat exchange device, temperature difference, and operation of the hot water circulation pump by the same control device. A characteristic diagram is shown. 2...Hot water circulation pump, 3...Relay contact,
5, 6...Thermistor for hot water temperature detection, 14, 1
8... Comparator, 19... Capacitor for timer time constant, 20... Variable resistor for charging, 22... Variable resistor for discharging, 24... Relay coil.

Claims (1)

[Scope of utility model registration request] In a circulation pump that forcibly supplies a heat medium in a heat source to a heat exchange device, causes the heat medium to transfer and receive heat through the heat exchange device, and returns the heat medium into the heat source after the transfer, the heat medium flows out from the heat source. temperature difference detection means for detecting a temperature difference between a heat medium flowing into the heat source and a heat medium flowing into the heat source and transmitting a circulation pump operation control signal when a predetermined temperature difference or more is detected; and a temperature difference detection means for periodically transmitting a circulation pump operation control signal. a control circuit for controlling the operation of the circulation pump in response to at least one operation control signal from the signals from both means; A control device for a circulation pump, comprising: